A displacement control value controls, for example, a control fluid working in a variable displacement compressor, and a discharge fluid supplied by opening and closing a valve. Iron powder or aluminum powder resulting from wear during operation in the variable displacement compressor is mixed in the discharge fluid. The powder has a diameter of about 10 μm, and thus adheres to sliding surfaces of the displacement control value therebetween. When a valve rod constituting one of the sliding surfaces is inclined with respect to an axis, a gap on the inclined side becomes narrower. The powder gets into the narrower portion, thus preventing the valve rod from operating according to setting. For this problem, improvement is required.
To this end, there is a known invention as shown in FIG. 3, for example, in which, in a solenoid valve including a bobbin 50 housed in a case 51 and wound with a coil 52, a core 53 provided at a central portion of the bobbin 50, constituting a magnetic circuit, a movable iron core 54 that is attracted toward the core by passing current through the coil 52, a rod 55 integrally joined to the movable iron core 54, a spool valve 56 pressed by the rod 55, a housing 57 that guides the spool valve 56, and a feedback chamber 58 formed by the spool valve 56 and a step of the housing 57, aligning grooves 59a and 59b are provided in the inner periphery of the housing 57 between an input port 59 and the feedback chamber 58 and between the feedback chamber 58 and the core 53, respectively, to align the spool valve 56 (Hereinafter, this invention is referred to as “Conventional Art 1.” See Patent Document 1, for example.).
There is also a known invention as shown in FIG. 4 in which, in a displacement control valve including a valve element 66 for opening and closing a control passage, a fixed iron core 61 for driving the valve element 66 to open and close it, a drive unit 60 including a tube 62, a plunger 63, a solenoid 64, and others, a rod guide hole 67 extending across the valve element 66 side and the drive unit 60 side, and a rod 68 slidably inserted through the rod guide hole 67 to operatively connect the valve element 66 and the drive unit 60, a gap between an outer peripheral surface of the rod 68 and an inner peripheral surface of the rod guide hole 67 is made larger on the low-pressure side than on the high-pressure side partially or entirely in a rod longitudinal direction so that foreign matter that has entered a space between the rod 68 and the rod guide hole 67 can be easily discharged (Hereinafter, this invention is referred to as “Conventional Art 2.” See Patent Document 2, FIG. 1, for example.).
Further, there is a known invention as shown in FIG. 5 in which, in a displacement control valve as in Conventional Art 2, a spiral groove 69 extending partially or entirely in a rod longitudinal direction is provided in an outer peripheral surface of a rod 68 or/and an inner peripheral surface of a rod guide hole 67 so that foreign matter that has entered a space between the rod 68 and the rod guide hole 67 can be easily discharged (Hereinafter, this invention is referred to as “Conventional Art 3.” See Patent Document 2, FIG. 2, for example.).